


don't leave me in the morning

by slowlange



Series: problematique [random explicit one shots] [4]
Category: Haikyuu!!
Genre: Anal Sex, Blow Jobs, Bottom Miya Osamu, Incest, M/M, Non-Consensual Somnophilia, Sibling Incest, Smut, Somnophilia
Language: English
Status: Completed
Published: 2020-12-18
Updated: 2020-12-18
Packaged: 2021-03-10 20:54:44
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,584
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28143447
Author URL: https://archiveofourown.org/users/slowlange/pseuds/slowlange
Summary: Atsumu has a boner.Nothing new. It shouldn’t be new, at least. They’re teenagers. Boners have been a part of their every day for years now. Osamu shouldn’t be standing before him, mouth molded into a tense ‘o’ as Atsumu’s cock twitches in his shorts.
Relationships: Miya Atsumu/Miya Osamu
Series: problematique [random explicit one shots] [4]
Series URL: https://archiveofourown.org/series/2045038
Comments: 12
Kudos: 307





	don't leave me in the morning

**Author's Note:**

> more! miyacest!
> 
> this is inspired by a rather incredible thread i've been following, i'll link it in the end notes if anyone wants to check it out!
> 
> anyway, osamu wants to fuck atsumu while he sleeps, and he's also a fucking perv. wonder how that's gonna go...
> 
> enjoy :)

Atsumu has a boner. 

Nothing new. It shouldn’t be new, at least. They’re teenagers. Boners have been a part of their every day for years now. He shouldn’t be standing before him, mouth molded into a tense ‘o’ as Atsumu’s cock twitches in his shorts.

It’ll go away. And once it does, he can tear himself away and turn over and fall asleep in his bed, only feet away from Atsumu.

So he lays and waits for the seemingly inevitable. Alas, it never came, though the minutes stretched on.

Osamu could feel himself stirring in his sweatpants the longer he kept his eyes trained on his brother’s dick. He’d always found Atsumu’s body interesting; from the hills of muscles that adorned his arms and torso, to the very girth that hung between his legs. He was more fascinated with what was new nowadays. Long sessions in the gym were to thank for Atsumu’s figure, and puberty was to thank for his newfound sex drive that loved to peek out every now and then, especially at night.

Because like Osamu had said to himself before: this  _ isn’t new _ . Scenarios, exactly like this, have played out before his very eyes and he’s managed to ignore it with ease and go about his night.

So why is he stuck here staring, wondering, _ fantasizing _ , this much?

He looks back at his sleeping brother, to the prominent tent that he can see all the way from his bed, and looks away all over again.

Osamu _ can’t _ . What he’s thinking about, what he wants to do right now…there’s no way he can do it. It would be incredible too, in a world where he could get away with it without ever needing to return. Because if he’s honest with himself, if he were to play the lead role in one of his most devastating fantasies, he will have crossed a gap so wide there would be no return to normalcy.

Atsumu already stood as one of his unhealthier fixations. There were times when his brother would be the only thought that circled his mind, jumping around and laughing with that annoying, intoxicating laugh of his.

As much as he feared the possibility and danger of latching onto something as precious and unrealistic as practicing this sort of intimacy with Atsumu, he still considered it. Weighed the pros and cons because this is  _ Atsumu _ he’s talking about. What kind of brother would be if he wasn’t willing to put everything on the line for him. For the love he  _ had  _ for him; the mere chance of them being able to share something like this.

His breath catches in his throat and he comes to the conclusion that he is indeed going to do it.

Atsumu is a deep sleeper, after all. 

Osamu caves in a pitiful, satisfying instant, convinces himself a peek at his naked cock isn’t so bad in the grand scheme of things. He’s curious. Wants to see what his brother looks like at his most intimate.

_ Though is it his most intimate?  _ Osamu considers that Atsumu’s lack of consciousness can be considered the most vulnerable state there is as he twists his thumbs about the waistband of his shorts and drags them down the ravenous meat of his thighs. Osamu hadn’t realized just how much muscle Atsumu had piled onto his bones until now, watching the elastic of his undergarments hug his skin to the point where it looks like it’ll slice through. So  _ thick… _

And his girth is an even more pleasant surprise. Osamu, in his youth, thought that he and Atsumu were completely the same in each and every way. Down to the dirty bits. 

He was wrong.

Atsumu provided a double threat, making up for what Osamu lacked in thickness, and he felt nothing but bubbling excitement in his stomach as he inched his face closer. Out of pure lust, he’d started breathing harshly from his chest, much like a starving animal presented a juicy slab of meat. He hadn’t the sense to stop, being that if Atsumu were a normal human being, these sounds would wake him in an instant.

It was a good thing Atsumu was far from normal.

He’s drawn to the musk of arousal that floats where Atsumu’s cock was previously trapped. Osamu, careful not to jostle the mattress too much while doing so, buries his nose into Atsumu’s crotch, the tip of it nuzzled against chestnut pubes. His smell is familiar and as it floods into Osamu’s nose, his boxers grow tighter. He considers for a moment what would happen if he let his tongue dart out of his mouth, let the warm, wet muscle curl about Atsumu’s dick, and work it’s way back up to the sweltering tip.

Pleased with the image and more than willing to explore his drive as Atsumu snores above him, he does exactly that, dragging his tongue along his shaft and pulling away the moment he laps a bead of the precum that dribbles from the slit. Its salty taste doesn’t cause him to recoil, much like he’s heard from his friends who’d also sucked cock. Atsumu, he tastes better than any girl Osamu has been with. Probably better than any other guy he’d ever consider hooking up with.

Atsumu has always been in his own arena, nowhere near the rest of the competitors. An inevitable winner in the game for Osamu’s love.

He wants more, cranes his head before letting his mouth cover the tip of his cock completely. Careful of making too many sudden movements, his pace stays measurably slow, taking brief pauses between each dip of his head, every kiss, and every lick.

When his jaw begins to hurt he pulls away from a short breather, looks at the job he’s done, assesses what he’s accomplished. Atsumu’s cock shimmers with spittle and jizz that spread down his shaft and onto his crotch, the slivers of moonlight that come through their blinds illuminating Osamu’s sin.

With Atsumu’s cock standing tall before him, gloating its massiveness and potential to please and destroy Osamu all at once, he finds little to no power to resist the hands that rush to undo his pants. There are seconds between the time it takes for him to kick his discarded undergarments to his side of the room and to sling a quivering leg over his waist and hover over his dick.

He wets two of his fingers and tries his best to be quiet as he opens himself up lewdly on top of him. Atsumu sleeps through it all, as he has been, but Osamu imagines he’s awake, corkscrewing his fingers inside of his tight hole all by himself, leaving kisses on his thighs and whispering sweet nothings into his ear as he brushes against his prostate.

Osamu bites down on his fist in an attempt to swallow the moan that wants to escape. It’s the pinnacle of something being so wrong in thought and theory, but feeling so right when executed. 

The urge to stroke himself to completion simmers when Osamu reminds himself that he wants to save the end for when Atsumu is inside of him and he’s able to fuck himself on him. Use him. Is he using him?

He supposes Atsumu is his own little sex toy right now, inanimate and existing for his pleasure only. Perhaps he is using him, but Atsumu is more than a toy. He loves him. The line he’s crossed, he’s crossing it  _ because  _ of that love.

Yes. That’s all.

He spreads his cheeks with tense hands as he lowers himself onto Atsumu, and almost instantly one of them flies up to cover his mouth as the pain of the stretch ripples through Osamu’s body. His thighs twitch from the strain of holding himself up and tears prick at the corners of his grey eyes but he keeps it together. Because if Atsumu wakes, this will have all been for nothing. Indulging in his sick and twisted fantasies in the only way he can, will have been for naught.

Atsumu’s cock fills him inch by inch after that, Osamu giving himself at least ten seconds with each increment. What was once burning turns into a soothing numbness, and his teeth slowly release his fists, clear marks left behind. As the adrenaline wears off and his head returns from the clouds, Osamu lets his head fall forward, hair in need of cutting falling over his eyes just for him to remember to take the time and capture Atsumu at this moment before it’s gone, fluttering from his fingertips and mingling into the air they breathe.

He looks gorgeous when he sleeps. Absolute silence replaces his active, obnoxious traits. Osamu loves when he can have a moment of peace with Atsumu, this one included. Sometimes they moved so fast, through school days, practices, their  _ lives _ , and Osamu felt he never took a moment to exist with his brother. There was a careful, delicate aura that surrounded him when they weren’t running without rest. It didn’t help that Atsumu was almost always ahead of everyone else. 

But his chest is the only part of his body that moves, outside of his fidgeting cock, and Osamu smiles before brushing a still strand of hair from his eyes and pressing his lips just beside long eyelashes. 

“I love you, ‘Tsumu,” he whispers in his ear as if he can hear it.

Perhaps it was a bad move to run the risk of waking Atsumu before he can fuck him, but Osamu loses his sense of tact when he pushes up with his legs and feels his cock dragging along the sides of his hole. He covers his mouth and shields the gasp that threatens to escape, sweet, delectable pleasure bubbling in his stomach and threatening to spill over.

When it’s just the tip that’s left, clinging onto his clenching heat, Osamu grinds back down, falling into a steady rhythm. His cheeks slap quietly against the front of Atsumu’s thighs, the sound an irresistible one. Against his more carnivorous needs he doesn’t speed up, keeps everything slow, and tries not to get too ahead of himself no matter how badly he wants to chase his orgasm full on. 

His free hand slides to pinch one of his nipples, twisting in a way he thinks Atsumu would. He’s always been aggressive, on the court and in private. But Osamu likes to think he would taper his impulses, control himself if it meant treating his brother with a balance between hostility and delicacy.

He imagines Atsumu is moving with him beneath his quivering legs, rocking his hips up to meet his desperate grind. Osamu doesn’t know what he’d do if it was real. If Atsumu were to grab him by the neck abruptly and take over. Maybe he’d cum in an instant.

The thought sends a strike of lightning down his spine and Osamu whimpers before bending over his brother’s sleeping body, ear barely beside his chest as he rides him faster. He feels like a slut, for a lack of better words. Riding his brother’s cock like it’s any old day and there’s nothing so deeply depraved and fucked up about his desires. But no one truly knew how long he’d been waiting for a moment like this, sitting back on his heels and enduring waves of arousal as they crashed over him day after day. Fighting his urges during practice as Atsumu’s muscles flexed with every set, every spike, every serve. It was torture, seeing him move like that and throw a show-stopping grin back at Osamu. He has no idea what he does to him.

It was the waiting the made him such a fucking slut, after all.

“Oh god,” He whispers, the words slipping past knitted fingers, “oh fuck ‘Tsumu  _ fuck _ …”

His cock is beginning to leak and Osamu catches it before he can make a mess too tricky to clean. He starts to stroke, careful with each flick of his wrist as he falls in sync with his hips. He can see the end, a bright, seizing light at the end of a dreadfully dark tunnel. His breathing becomes mangled and his eyes screw shut as thrusts become sloppy and he struggles to manage himself up. For a moment, he swears he feels Atsumu’s fingertips brushing his thighs.

It’s so real he shakes when he finishes into his hand, eyes snapping open with a cry. To who? Who knows. Maybe God.

Cum spurts into his hand and onto his shirt, which he’d use to cover his dick in preparation for this kind of orgasm. He fucks himself through it until he feels Atsumu shooting hot jizz inside of him. Osamu jolts at the sensation at first but wishes he’d waited to orgasm, so they could have experienced it together. 

When he’s sure there’s no way Atsumu will wake he takes a moment to catch his breath, feeling the heat on his own face as it bounces off Atsumu’s stomach. It’s all he can do; sit there, and let the reality of what he’d done wash over him.

He has less regret than he would expect, a hazy smile spread across his face. His climax felt like the crashing down of all his pent up desire, and for now, he was content. Tomorrow night would be a different story, but it was a problem for his future self.

Osamu pulls out, bends down to lick his brother clean with an eager tongue and a finishing kiss to the tip of his flaccid prick before dressing him again. The ethics behind it feel off, he considers as he tucks himself back into bed, but anyone looking from the outside in wouldn’t understand.

This is his love. And this is how he shows it.

  
  


* * *

  
  


The next morning, Osamu wakes up to Atsumu peering over him as he lays in his bed.

“‘Tsumu?” Osamu rubs the last dregs of sleep from his eyes.

“I had a dream about you last night?”

His index finger freezes as it drags past his left eye. “A dream?”

“Yeah.”

“...Was it a good dream.”

Atsumu shrugs with a nonchalant expression splayed across his face. “I dunno, you tell me.”

Osamu flushes. There’s no way. He was  _ positive  _ Atsumu had slept through it all.

But then again, the faint touches to his thighs that he thought he’d imagined as he came on his cock last night…

_ Oh, God.  _ He hadn’t imagined them?

“I-I don’t understand.”

“All I’ll say,” Atsumu’s hand reaches to caress the side of his face, and Osamu freezes in shock, “is that I absolutely would not mind having that dream again.”

Atsumu’s hand burns like lava against his skin. Osamu has barely registered the words that left his lips before his brother leans over the bed’s railing to press a quick kiss to his forehead.

“I’d like to be awake this time though if that’s alright.”

And as Atsumu saunters out of the room, bath towel in hand and a sway in his hips, Osamu considers himself lucky that his means of showing endearment are shared. 

“Tonight?” He blurts out, excitement clear in the way he grips onto his sheets, afraid he’ll fall over from the raw shock of it if he lets go.

“Sure!” Atsumu calls out from the bathroom. The back of Osamu’s head burns and he grins, throwing himself back into his bed and pressing his reddened face into his pillows.

Thank god.

**Author's Note:**

> follow me on [twitter](https://twitter.com/slowlange) and check out the [thread](https://twitter.com/br0nigiri/status/1336436692144644097?s=20) here!
> 
> thank you for reading!! 
> 
> will most likely be back with more because my third eye is open now...


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